Vibratory parts feeders are commonly known apparatus for providing oriented parts from a mass of disoriented parts, or for transporting parts along a processing path. In providing oriented parts, a vibratory parts feeder typically includes a vibratory bowl which is driven by a vibratory drive unit. The bowl is internally configured, typically with a helically oriented path, to transport the parts under vibratory action to a bowl exit location near the top of the bowl.
A variety of mechanisms for orienting the parts are known to be operatively associated with a vibratory bowl apparatus. U.S. Pat. No. 4,436,197, for example, discloses a pair of spaced-apart rails which slope downwardly so that properly oriented parts may slide down the path to the lower section of the track. A gate associated with the track permits only those parts having the desired orientation to continue sliding down the track. U.S. Pat. No. 3,578,142 utilizes a different approach in that the parts transportation path of the bowl is configured to define an adjustable slot for receiving only parts having a particular orientation therein. As the parts are thereafter transported to the exit location near the top of the bowl, the adjustable slot manipulates the parts into the desired orientation.
A common problem associated with serially providing oriented parts from a vibratory bowl is maintaining the orientation of the properly oriented parts under the continuing vibratory action. As a solution to this problem, several vibratory parts feeders utilize some type of top confinement mechanism to minimize further agitation of the oriented parts. For example, U.S. Pat. Nos. 3,907,099, 4,206,539 and 5,191,960 include a downwardly sloped parts track having fixed top surface for confining the orient parts to the track. Other known vibratory parts feeders utilize hinged top confinement structures that are moveable away from their confining positions to thereby allow access to the parts orientation track for clearing jams and performing other maintenance related functions.
Common problems associated with such known hinged confinements include excessive movement of the top confinement mechanism due to inadequate securing of the hinge mechanism, and an adequate lock operable to fixedly position the top confinement member as it is returned to its operating position. Such hinged confinement mechanisms have not gained popularity since, due to the nature of the vibratory action, confinement structures inadequately secured to the vibratory bowl create dead spots and operation inefficiencies that result in fluctuations in feed rate. One solution to the adequate securing problem is disclosed in U.S. Pat. No. 4,700,827 as including a top confinement structure with a series of zero lash hinges at one end and a corresponding series of clasp-type latches at the other. The problem of lack of fixed positioning is not discussed in this reference.
What is therefore needed is a top confinement apparatus that is moveable to permit access to the parts orientation track, but which securely attaches in a repeatably accurate location to the vibratory bowl in its operable position to provide a reliable and accurate top confinement mechanism.